Light stabilized hydrocarbon fuel



United States Patent 3,223,496 LIGHT STABILIZED HYDROCARBON FUEL Walter F. Schoen, South Holland, Ill., assignor to Sinclair Research, Inc., Wilmington, Del., a corporation of Delaware N 0 Drawing. Filed July 5, 1962, Ser. No. 207,765 5 Claims. (CI. 44-63) This invention relates to the stabilization of hydrocarbon fuels containing organo lead anti-knock compounds and to the inhibition or reduction of octane number degradation of such fuels.

Hydrocarbon fuels under present requirements of highcompression engines almost universally contain antiknock compounds, principally, organo-lead compounds such as tetra lower alkyl lead compounds. Both automotive and aircraft fuels are commonly blended with tetraalkyl lead compounds before use. Such blending imposes a point of instability in the finished fuel, since the tetra-alkyl lead compounds are susceptible to decomposition by exposure to sunlight during the blending, storage and handling operations with consequent formation in the fuel of deposits which contain lead, formation of haze, loss of some anti-knock value and lessened performance in the engine as a result of undue octane number degradation.

It is therefore an object of this invention to provide means for protecting such fuels against decomposition of lead anti-knock compounds in the presence of sunlight. Another object of this invention is to provide means for stabilizing lead-containing hydrocarbon fuels for internal combustion engines during the manufacturing, handling and storage of such fuels prior to their use. It is also an object of my invention to provide fuels containing tetra lower alkyl lead compounds in which there is no substantial degradation of octane number of the fuel, i.e. there is no substantial loss in performance characteristics. A still further object of this invention is to prevent plugging of fine gasoline filters caused by the formation of lead-containing deposits. Some improvements in gasoline pumping apparatus reducing exposure of the fuel to sunlight have been made, yet lead deposits still cause plugging of fine gasoline filters provided to protect intricate carburetor systems of internal combustion engines.

The above objects may be accomplished by practicing this invention which comprises adding to a gasoline containing a tetra-lower alkyl lead anti-knock agent a small but effective amount of a gasoline soluble phenol-substituted benzotriazole. The stabilizing additive compounds of this invention can be further defined in terms of the general formulae 3,223,496 Patented Dec. 14, 1965 wherein R is hydrogen or a substituent such as a lower alkyl radical containing, for instance, from about 1 to 5 carbon atoms, in straight or branched chain arrangement.

The benzotriazoles may be prepared by first coupling an ortho-nitrobenzene diazonium compound with a phenolate and then reducing the ortho-nitro azo phenol. The phenol may have a lower alkyl carbon atom group, for instance from about 1 to 5 carbon atoms in the para or other position. The ortho-nitrobenzene diazonium compound may be prepared in a known manner by diazotizing ortho-nitroaniline with sodium nitrile and dilute hydrochloric acid. Coupling can be accomplished, for instance, by reacting an alkaline salt of a para lower alkyl substituted phenol with the ortho-nitrobenzene diazonium chloride to form the 2-(2-nitrophenylazo)-substituted phenol. The compound can be reduced to the triazole by refluxing in the presence of zinc. Phenol or other lower alkyl phenols may be employed instead of the para-substituted compounds as may be the other benzotriazoles to give the various gasoline-soluble N-hydroxy phenyl benzotriazoles.

Among the benzotriazoles falling within the definition of useful decomposition retarders for the present invention there are several which are preferred. Thus it has been found that satisfactory results have been obtained by using in the base hydrocarbon gasoline containing a small amount of tetra-lower-alkyl lead anti-knock agent, stabilizing amounts of 2[2'-hydroXy-5'-(methyl, ethyl, butyl etc.) phenyl] benzotriazole. The additive may be substituted with other non-deleterious constituents. The additive compound of this invention is incorporated into the hydrocarbon fuel in amounts sufficient to retard the decomposition of the tetra-lower-alkyl lead anti-knock agent and generally this amount may be from about 0.05 to 2, preferably about 0.5 to 2 weight percent.

The tetra alkyl lead compounds employed in the improved gasoline composition of this invention include, for instance tetra methyl lead, tetra ethyl lead or a tetraalkyl lead compound containing both methyl and ethyl radicals. Generally the gasoline may contain from about 0.5 to 4.5 ccs. or even about 6 ccs. of tetra-alkyl lead compound per gallon of gasoline.

Gasoline which is the major component of this invention is usually a blend of hydrocarbon mineral oil fractions boiling primarily in the approximate range of about to 425 F. The gasoline will contain varying proportions of paraflins, olefins, naphthenes and aromatics derived by distillation, cracking and other refining and chemical conversion processes practiced upon crude petroleum fractions. Straight run gasolines, gasolines derived from cracking gas oil, gasolines or reformate from reforming straight run naphtha over a platinum-alumina catalyst in the presence of free hydrogen, etc. are components frequently used in making up a gasoline composition. A typical premium gasoline, besides a small amount of a tetra-lower alkyl lead compound as an antiknock agent, may also contain small amounts of other constituents to impart various properties to the gasoline in its use in internal combustion engines, e.g., scavengers, corrosion inhibitors, etc. Such leaded gasolines frequently have a Research Method octane number of about 90 to and a Motor Method octane number of about 80 to 98.

Examples of the defined additive compound and illustrations of the gasoline compositions containing various amounts of the additive compound and the beneficial results derived from the presence of the additive compound in leaded gasoline are set out below. It is to be understood that the examples are illustrative only and do not limit the scope of the invention.

3 Example I To a sample of a commercial gasoline consisting of 12.5 weight percent olefins, 34.5 weight percent aromatics, 53 weight percent saturates, and 3 cc. per gallon of tetra-ethyl lead (added in the form of Motor Mix which contains 59.2% tetra ethyl lead 13.0% ethylene dibromide, 23.9% ethylene dichloride and 3.9% hydrocarbon diluent, dyes, etc.) was added one weight percent of 2(2-hydroxy 5 methylphenyl) benzotriazole. The treated sample and an untreated sample of the same leaded gasoline were stored in identical clear glass bottles which were then placed in sunlight for three days. At the end of the three day period, the untreated sample not containing the benzotriazole was cloudy in appearance and a substantial amount of sediment had collected, but the treated sample containing the benzotriazole was clear and only a small amount of sediment was formed.

Example II A gasoline having an API gravity of 57.1 and an ASTM distillation of:

IBP 90 a Reid vapor pressure of about 11.0 and containing about 12.5% olefins, 34.5% aromatics and 53.0% saturates (FIA), typically contains the following components:

Components: 4 Volume percent Light straight-run gasoline 10.0 Alkylate 20.0 Light fluid catalytically cracked gasoline 28.0 Xylenes 5.0 Straight run naphtha reformate 31.0 n-Butane 6.0

Two 100 cc. samples (I and II) of the base gasoline described above, containing 6 ml. per gallon of tetraethyl lead (added as Motor Mix) were stored in clear glass bottles for 8 days and exposed to sunlight. Sample I was blank while Sample II also contained about 1 weight percent 2(2'-hydroxy-5 methylphenyl) benzotriazole. After the test period the samples were tested by the Octane Rating Sample Additive Motor Method Research Method I None II 2(2-hydr0xy-5 methyl phenyl) benzotriazole.

These results show that the octane number degradation of a leaded gasoline composition containing the additive of this invention was substantially reduced or inhibited, indicating that the blank sample experienced a greater decomposition of the lead additive due to its exposure to sunlight.

It is claimed:

1. A leaded gasoline composition consisting essentially of base hydrocarbon gasoline, a small amount of tetralower-alkyl lead anti-knock agent sufficient to reduce knock and a gasoline soluble N-hydroxy lower alkyl phenyl benzotriazole in an amount sufficient to retard decomposition of said anti-knock agent when said gasoline is exposed to sunlight, said lower alkyl having 1 to 5 carbon atoms.

2. The composition of claim 1 wherein the benzotriazole is a 2(2'-hydroxy-5'-lower alkyl phenyl) benzotriazole.

3. The composition of claim 2 wherein the anti-knock agent is tetra-ethyl lead.

4. The composition of claim 1 wherein the benzotriazole is 2(Z-hydroxy-5-methylphenyl) benzotriazole.

5. The composition of claim 3 wherein the 2(2'-hydroxy-5-lower-alkyl phenyl) benzotriazole is provided in amounts of about 0.5 to 2 weight percent of said composition.

References Cited by the Examiner UNITED STATES PATENTS 2,224,904 12/1940 Elley et a1. 44 '59 2,426,709 9/1949 Roddy 44 59 3,018,269 1/1962 Bruno 252 500 DANIEL E. WYMAN, Primary Examiner. 

1. A LEADED GASOLINE COMPOSITION CONSISTING ESSENTIALLY OF BASE HYDROCARBON GASOLINE, A SMALL AMOUT OF TETRALOWER-ALKYL LEAD ANIT-KNOCK AGENT SUFFICENT TO REDUCE KNOCK AND A GASOLINE SOLUBLE N-HYDROXY LOWER ALKYL PHENYL BENZOTRIAZOLE IN AN AMOUNT SUFFICIENT TO RETARD DECOMPOSITION OF SAID ANTI-KNOCK AGENT WHEN SAID GASOLINE IS EXPOSED TO SUNLIGHT, SAID LOWER ALKYL HAVING 1 TO 5 CARBON ATOMS. 